performance impact of large /etc/hosts files
xfb52 at dial.pipex.com
Tue Dec 11 09:00:11 PST 2007
Erich Dollansky wrote:
> But new sites have new stuff I would like to be filtered out. To make
> these experiences as rare as possible, I collect from friends and the
> Internet hosts files to filter as much as possible.
> This resulted in a pretty large file meanwhile.
> But the Internet looks much more usable for me now.
Assuming I've understood your initial post correctly, then I do the
same, redirecting some dozen ad sites to a local web server. With a
dozen or so aliases I've never noticed any difference in performance,
but I suspect you have rather more than that :-) I could never quite be
bothered to maintain the list once I'd filtered ads from the sites I use
I think the answer to your original question is going to be "look at the
source code". If your hosts file is really that large then I suspect it
will be having a performance effect and only you can judge if it's
significant or not. Large hosts files are not the future, so
performance improvements in the future are unlikely, I would say.
I'm pretty sure you could also do the same with a local DNS server, if
you wanted to "abuse" it in this way, and that would *probably* be
faster since the code would expect to deal with large lists of hosts.
Been a while since I did anything like that, though, and never on the
scale you seem to be describing.
There's no clean solutions to getting different lookups per-user that I
am aware of, but unless your host is also performing some service that
involves a lot of name resolution then why care? (And if it is, you
shouldn't be using it as a general web browser :-))
Unclean solutions might include something like making the hosts file
point to some automounted directory which changed per user, but you'd
have to be sure that you saw a valid hosts file at boot time. Fiddling
with symlinks in rc scripts could do that, I'm sure.
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